Yahoo was once a giant in the internet industry, but the firm has more recently seen its market share snatched by Google and also the incredible rise of Facebook, the social network which now has more than 800m members world.

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In an emailed statement, Yahoo said: "Yahoo has a responsibility to its shareholders, employees and other stakeholders to protect its intellectual property.

"We must insist that Facebook either enter into a licensing agreement or we will be compelled to move forward unilaterally to protect our rights."

A person familiar with the matter said that the dispute appears to be over up to 20 different patents covering social networking technology, online advertising and personalisation.

Facebook said that it only learned about the threat of legal action yesterday, saying: "We haven't had the opportunity to fully evaluate their claims."

While patent battles are a common feature of the wider technology industry, Facebook and the social networking market has so far remained relatively immune.

To protect its technology, Facebook is understood to own around 56 patents, but the firm has filed more than 410 applications at the US patents officer over the past 18 months, according to asset management firm M. CAM.

Yahoo is thought to view patents as a viable strategic way to raise funds and also hinder its rivals. The firm also brought a similar patent claim against Google in the run-up to the US firm's initial public offering in 2004.

After Yahoo acquired search advertising firm Overture, it was able to force Google to hand over 2.7m shares, which were worth $230m when the company went public.

However, a person familiar with Yahoo's situation denied that the patent move was motivated by Facebook's IPO, but instead said that it was part of new Yahoo chief executive Scott Thomson's bid to boost all areas of the business.